1. Field of the Invention
The invention discloses a lighted socket, or an attachable light socket collar, within a light string system. The socket or collar itself is illuminated when the bulb is removed from the socket or the bulb is otherwise malfunctioning. A separate illumination element is provided either as part of the socket itself or is attached thereto and is coupled to both power circuitry and associated control circuitry within the socket such that when the light bulb is removed or malfunctions, the socket lighting element illuminates and identifies the specific and exact light bulb within the string that requires replacement. In a particularly preferred embodiment, the resistance of the separate illumination element is properly selected to maintain substantially the same voltage across the entire light socket, including the light socket illumination element and defective bulb, such that constant current is maintained in the light string. This condition allows the remaining functional bulbs to all remain on and in a safe operating condition.
2. Description of the Prior Art
U.S. Pat. No. 6,518,707, Issued Feb. 11, 2003 to Gershen et al. (hereinafter “Gershen et al.”) discloses a voltage detector for a series light circuit. Gershen et al.'s voltage detector takes the form of a resistor, one each connected in parallel with each lamp within the light string. (FIG. 5.) Each resistor is coated with thermochromatic paint that changes from opaque to clear when sufficient power is applied across the resistor. The failure of a bulb in the light string causes the resistor to consume the majority of the light string's circuit power and dissipate that power as heat. When the thermochromatic paint turns clear due to the heat of the engaged resistor, the original color of the resistor is revealed for identification by the user. (Col. 4, 11. 31-43.) However, Gershen et al. does not disclose how the resistor itself is returned to its original state (i.e. recoated with the thermochromatic paint) once the defective bulb burns out and is replaced. (See FIG. 2 showing the resistor as part of the socket base and not as part of the replaceable bulb.)
In order for Gershen et al. to work, the resistor must be sized sufficiently such that enough heat is generated within the resistor upon bulb failure so as to activate the thermochromatic paint. As disclosed in Gershen et al., this typically results in a resistor value in the tens of kilo-ohms, which necessarily reduces the voltage within the light string to a near zero value. Thus, none of the functioning bulbs on Gershen's LED light string are provided sufficient bias voltage or current to remain illuminated upon bulb failure. The faulty bulb is capable of being located, but the string is inoperative. (Col. 4, 1. 44 to col. 5, 1. 14.)
Gershen et al. also discloses other forms of voltage detectors, such as audible alarms (Col. 5, 1. 35.) and electroluminescent lamps (col. 5, 1. 45 et seq.). Each of these disclosed arrangements have limitations that either prevent the remaining, non-failing bulbs on the light string from remaining lit or do not permit more than a small number of bulb/socket failure detections.
Thus it is an object of this invention, and the failure of the prior art to-date, to deliver a light string in which failed bulbs and/or their associated sockets, using any lighting technology, are clearly identified by visual means and in which the remaining, non-defective bulbs within the light string remain on.